Microsoft Dynamics CRM 4.0 now uses the native mail merge feature of Microsoft Word while performing a mail merge, making Mail Merge available through both the Microsoft Dynamics CRM 4.0 Outlook Client as well as the Web Client. 

Functionality available when using either client for Mail Merge includes:
§  Create a Mail Merge from within Microsoft Dynamics CRM.
§  Create and save Mail Merge templates in Microsoft Dynamics CRM for re-use.
§  Pull data from multiple entities for mail merge templates.

Additional functionality available when creating a Mail Merge from the Outlook Client includes:
§  Create a Quick Campaign from a Mail Merge window.
§  Create Activities generated from within the Mail Merge and contained in the Quick Campaign record.
§  Assign Activities to another user.